自应力约束条件下超高强混凝土复合增强增韧机理及抗侵彻特性

Protective materials are moving in the direction of strengthening and toughening, lightweight, multifunctional. A new composite protective material RPC400-600 was obtained in this study. The Reactive Powder Concrete (RPC) with ultra-high strength was used as matrix. Shape Memory Alloy (SMA) fiber, steel fiber and ceramic microspheres were added by the constant composition method to reinforcing and toughening. The self-stress generated from the restriction of steel fiber to tobermorite crystallization expansion was investigated and its calculation method was put forward by observing the crystal growth of C-S-H gel and tobermorite in RPC material with low water binder ratio under different hydrothermal conditions. The strengthening and toughening mechanism of the restriction of SMA fiber to the RPC composite material was investigated and the calculation method of its self-stress was put forward by analysing the shape memory effect of SMA fiber on the RPC matrix. Dispersion strengthening was realized by adding ceramic microspheres and the interface structure relation between ceramic microspheres and the RPC matrix was analysed. The damage evolution law of RPC composite protective material with self-stress was established and the theoretical model of anti-penetration were put forward based on the anti-penetration experiment. This study provides theoretical basis for the design of strength and toughness of materials with high performance and has a significant contribution to the security of national defense project.

针对国防防护材料强韧化的迫切需求，本课题以超高强RPC复合材料为基体，通过掺入SMA和钢纤维及陶瓷微珠实现对RPC的复合增强增韧，并制备出新型的RPC400-600复合防护材料。主要研究内容：研究不同水热条件下低水胶比RPC材料的C-S-H凝胶和托贝莫来石生成规律，揭示托贝莫来石膨胀及钢纤维约束其膨胀的自应力产生机制，建立晶体生长约束状态下托贝莫来石晶格畸变引起的RPC自应力计算方法；研究SMA形状记忆效应约束RPC基体产生的自应力变化规律，揭示SMA约束RPC复合材料的增强增韧机理，建立SMA约束自应力的计算方法；分析超强硬陶瓷微珠与RPC基体之间的界面结构关系，揭示陶瓷微珠对RPC基体的弥散增强机理；通过抗侵彻实验和理论分析，研究自应力约束下RPC复合防护材料损伤演化规律，建立抗侵彻评价方法。本项目的研究为混凝土材料增强增韧设计提供理论依据，对提高我国国防防护工程的安全性具有重要意义。

在军事防护领域，相比普通强度混凝土，超高性能混凝土防护性能大大提高，未来可广泛应用于弹药存储库、导弹发射井、控制指挥中心等具有重大价值目标的防护，同时，在坦克披挂复合装甲领域，也有鲜明的应用前景。本项目拟通过在自应力约束，对超高性能混凝土的增强增韧机理进行研究，并利用超高性能混凝土制作防护靶材，探索了对穿甲弹的聚能射流防护效应。.（1）通过高强骨料（石英砂、电熔刚玉、陶瓷微珠）与骨料分形级配显著改善RPC内部骨料与基体的结合，从而提升超高性能混凝土的结构强度。.（2）分析不同纤维形貌、长径比、切碎钢纤维等各类纤维组合等对超高性能混凝土的增韧增强机制。为了更大幅度提升超高强混凝土强度及抗侵彻特性，开展了具有自锚固功能的“双Y型”钢纤维制备技术研究，对“双Y型”钢纤维在混凝土中的增强作用机理开展研究，提出了双Y型钢纤维自锚固作用机制。.（3）在长期水热合成条件下，开展超高性能混凝土膨胀性能与变化规律实验。运用非破损检测手段，对长期高温养护材料质量变化、动弹性模量变化、超声波变化等对超高性能混凝土的结构与性能进行评估，获得了在长期水热合成条件下，RPC膨胀性能稳定理论依据。.（4）研究不同水热条件下低水胶比RPC材料的C-S-H凝胶和托贝莫来石生成与转化规律，揭示托贝莫来石膨胀及钢纤维约束其膨胀的自应力产生机制，建立晶体生长约束状态下托贝莫来石晶格畸变引起的RPC结构膨胀变形预测。 .（5）探究不同种矿物掺加料（矿渣，石英粉，粉煤灰）组成混合胶凝材料对RPC基体水化相以及对 RPC结构性能的影响。分析了矿渣与粉煤灰等矿物掺和料替代石英粉与水泥的可行性，从而大幅度降低制备RPC材料的生产制作成本。.（6）开展不同强度级别的超高性能混凝土对聚能装药系统进行防护效应研究，得出不同强度等级下超高性能混凝土的防护效应参数。为后续超高性能混凝土运用与防护领域提供制备参数与防护理论基础。